Comdemo is a full duplex
terminal program. It recognizes
most
of the more common ANSI
control sequence such
as cursor
location and screen attributes.
You can use Comdemo to
dial up a BBS or communicate
with RS-232 equipment.

The Serial Port is harder
to interface than the
Parallel Port. In most
cases, any device you
connect to the serial
port will need the serial
transmission converted
back to parallel so that
it can be used. This can
be done using a UART.
On the software side of
things, there are many
more registers that you
have to attend to than
on a Standard Parallel
Port. (SPP)